This invention relates generally to yttrium phosphate and a method for producing it in commercial quantities, and is particularly concerned with a pure or single phase yttrium phosphate having the xenotime crystal structure and a process for synthesizing it without utilizing extremely high temperatures.
In recent years many researchers have explored the use of yttrium phosphate in the field of ceramic materials. Yttrium phosphate appears to be valuable for use in laminate composites, as a fiber-matrix interface in ceramic matrix composites and as coatings for thermal protection. It appears to be particularly useful as a coating because of its resistance to expansion when exposed to high temperatures.
Although the synthesis of yttrium phosphate by various researchers has been reported, either via expensive high-temperature solid state reactions and wet chemical precipitation, large quantities of yttrium phosphate for commercial applications do not appear to be available. Furthermore, it is very important in the field of ceramic materials processing that any yttrium phosphate utilized be free of secondary phases and other impurities. Thus, there is a distinct need for the development of relatively inexpensive methods to synthesize large quantities of pure or single phase yttrium phosphate, especially yttrium phosphate having the xenotime crystal structure.